1. Field of the Invention
The present invention relates to an ink discharge detecting method for an ink jet recording apparatus, and the ink jet recording apparatus.
2. Related Background Art
Conventionally, a variety of recording apparatuses for recording onto a recording medium such as a paper or OHP sheet have been proposed, and especially, an ink jet recording apparatus which directly jets the ink from a recording head onto a recording sheet has gained wide acceptance as a recording apparatus having the advantages of low running cost and silent recording operation.
On the other hand, the method for detecting that the amount of ink has decreased in such an ink jet recording apparatus involves optically detecting a float moving up or down within an ink tank, or detecting the variation in resistance between electrodes provided within an ink tank.
However, the above conventional methods had a drawback that since a detecting member such as a float or electrodes was necessary within the ink tank, the detecting member had to be also exchanged integrally with the cartridge to be exchanged when the amount of ink within the ink tank decreased, for example, in the case of a disposable recording head of the cartridge type in which the recording head was formed integrally with the ink tank, so that costs and waste increased.
Further, the above conventional methods involved detecting analogue variation of ink quantity which resulted from decreasing amount of ink within the ink tank, whereby if the detected result was below a preset threshold, the ink absence was detected, at which time the ink within the recording head was not completely absent in practice, with the result that the decrease in the amount of ink was detected while a slight amount of the ink was left within the ink tank. Accordingly, there was a problem that because the waste ink unusable for the recording was produced, the running costs increased. Also, there was a problem that the ink level within the ink tank shifted up or down, along with the movement of the ink tank, bringing about malfunctions.
The present invention is devised to resolve the above-mentioned problems of the conventional art, and its object is to provide an ink jet recording apparatus and an ink discharge detecting method in which the decrease in ink remain or undischarge of ink can be securely detected with the amount of waste ink unusable for the recording reduced.
Also, it is another object of the invention to provide an ink jet recording apparatus for recording using a recording head which discharges heated ink onto a recording medium through discharge ports, characterized by comprising temperature detecting means, which is contactable with the ink discharged through said discharge ports, for detecting temperature change arising upon contact with said ink, positioning means for positioning said recording head and said temperature detecting means at relatively opposed locations so that the ink discharged through said discharge ports make contact with said temperature detecting means, and discharge detecting means for detecting discharge or undischarge of ink based on a detecting result of said temperature detecting means.
Also, it is another object of the invention to provide an ink jet recording apparatus for recording using a recording head having a plurality of nozzles which discharges the ink, characterized by comprising discharge detecting means for detecting the presence or absence of ink discharge from said recording head, varying means for varying the number of discharged ink droplets per unit time, and a control circuit for controlling the number of discharged droplets per unit time in making discharge detection by said discharge detecting means to be different from that during the recording, using said varying means.
Also, it is another object of the invention to provide an ink jet recording apparatus for recording using a recording head having a plurality of nozzles which discharges the ink, characterized by comprising discharge detecting means for detecting the presence or absence of ink discharge from said recording head, varying means for varying the volume of discharged ink droplets per unit time, and a control circuit for controlling the volume of discharged droplets per unit time in making discharge detection by said discharge detecting means to be different from that during the recording, using said varying means.
Also, it is another object of the invention to provide an ink jet recording apparatus for recording using a recording head having a plurality of nozzles which discharges the ink, characterized by comprising discharge detecting means for detecting the presence or absence of ink discharge from said recording head, and selecting means for selecting the discharge state from each discharge port of said recording head when discharge detection is made by said discharge detecting means, said recording head provided with a discharge port array having a plurality-of discharge ports arranged.
Also, it is another object of the invention to provide an ink jet recording apparatus for recording using a recording head having a plurality of nozzles which discharges the ink, characterized by comprising discharge detecting means for detecting the presence or absence of ink discharge from said recording head, input means for indicating the start of discharge detection, and a control device for controlling discharge detection with said discharge detecting means to be performed periodically or when input is made into said input means.
Also, it is another object of the invention to provide an ink discharge detecting method of an ink jet recording apparatus for recording using a recording head which discharges the ink onto a recording medium through discharge ports, characterized by including a process of discharging the ink from said discharge ports to make contact with an objective, a process of detecting the physical change produced in said objective by the discharged ink, and a process of detecting the discharge or undischarge of ink based on a detected result of said physical change.
Also, it is another object of the invention to provide an ink discharge detecting method of an ink jet recording apparatus for recording using a recording head in which the discharge direction of the ink discharged through a plurality of discharge ports onto a recording medium may lie in a horizontal direction or oblique to the horizontal direction, characterized by including a process of discharging the ink from said discharge ports to make contact with an objective, a process of detecting the physical change produced in said objective by the discharged ink, and a process of detecting the discharge or undischarge of ink based on a detected result of said physical change, wherein when discharge detection is made, the ink is discharged selectively from the discharge ports located upward in a vertical direction, among discharge ports of said recording head.
Also, it is another object of the invention to provide an ink remain detecting method of an ink jet recording apparatus for recording using a recording head which discharges the ink through discharge ports onto a recording medium, characterized by including a process of discharging the ink from said discharge ports to make contact with an objective, a process of detecting the physical change produced in said objective by the discharged ink, and a process of detecting the ink remain based on a detected result of said physical change.
Also, it is another object of the invention to provide an ink discharge detecting method performed with an ink jet recording apparatus having a recording head having a plurality of nozzles which discharges the ink, and discharge detecting means for detecting the presence or absence of ink discharge from said recording head, characterized in that the number of discharged ink droplets per unit time is made variable, so that the number of discharged droplets per unit time in making discharge detection may be different from that during the recording.
Also, it is another object of the invention to provide an ink discharge detecting method performed with an ink jet recording apparatus having a recording head having a plurality of nozzles which discharges the ink, and discharge detecting means for detecting the presence or absence of ink discharge from said recording head, characterized in that the volume of discharged ink droplets per unit time is made variable, so that the volume of discharged droplets per unit time in making discharge detection may be different from that during the recording.
With the above constitution, if one page of recording is terminated, the carriage is moved to a position at which the recording head is located opposite a cap. Then, the ink is discharged through the nozzles of the recording head onto a temperature detecting element within the cap. Temperature change of the temperature detecting element upon contact with the ink is output from a detecting circuit, and the normal discharge of ink is detected by discharge detecting means.